Receiving calls while on a call

Have you activated Call Waiting?

Do you have Voice Mail feature?

Respond to a second call on the same line

If you’re on a call and receive a second call on the same line, do one the following:

• Ignore the call and send it to voicemail: Tap Ignore.
• End the first call and answer the new one: When using a GSM network, tap End + Accept. With a CDMA network, tap End and when the second call rings back, tap Accept, or drag the slider if iPhone is locked.
• Put the first call on hold and answer the new one: Tap Hold + Accept.
• With a call on hold, tap Swap to switch between calls, or tap Merge Calls to talk with both parties at once. See Start a conference call.
• Note: With CDMA, you can’t switch between calls if the second call was outgoing, but you can merge the calls. You can’t merge calls if the second call was incoming. If you end the second call or the merged call, both calls are terminated.
• Note: On models with Dual SIM, when you’re on a phone call, any incoming calls on your other line go directly to voicemail (if available from your carrier); you won’t receive missed call notifications.
• If you set up conditional call forwarding (if available from your carrier) from one line to another when a line is busy or not in service, the calls don’t go to voicemail; contact your carrier for setup information.

While on a call on iPhone - Apple Support

https://support.apple.com/guide/iphone/while-on-a-call-iph3c9951d7/ios

Set up call forwarding or call waiting (GSM)

1. Go to Settings  > Phone.
2. Tap any of the following:

• Call Forwarding:  appears in the status bar when call forwarding is on. You must be in range of the cellular network when you set iPhone to forward calls, or calls won’t be forwarded.
  • On models with Dual SIM, choose a line.
• Call Waiting: If you’re on a call and call waiting is turned off, incoming calls go directly to voicemail.
  • On models with Dual SIM, call waiting works only for incoming calls on the same line.

For CDMA accounts, contact your carrier for information about enabling and using these features.

For information about conditional call forwarding (if available from your carrier) when the line is busy or not in service, contact your carrier for setup information.

Manage incoming calls on iPhone - Apple Support

https://support.apple.com/guide/iphone/manage-incoming-calls.../ios